This proposal examines the hypothesis that impaired serial order control for coordinated action is an underlying functional deficit common to reading impairment and the non-reading behavioral correlates of specific reading retardation. Under a neuropsychological frame of reference, various measures of coordinated unimanual and bimanual action, motor speech, and expressive language are examined, with particular emphasis on the interaction between rate and timing precision or rate and serial order control as the dimensions which may best characterize the disorder. Emphasis on the motor system implies no causal relationship between movement disturbances and reading retardation. On the other hand, the motor system is well suited for the objective analysis and decomposition of temporal variables in complex behavior that are shared by speech, expressive language, and skilled action. The study focuses on adolescents and adults with specific reading disabilities to examine which aspects of serial order control may be developmentally invariant. It compares male and female adolescents with specific reading disability; and it uses a matched "pathological" control group of adolescents with specific learning disabilities who are reading at grade level to test whether the presumed deficit of serial order control is particular to reading retardation or common to various learning disabilities.